2) Micro Bio Lab Practical (Endospore & Acid-Fast)

What is the purpose of the endospore stain?

Differential stain; Stain & visualize endospores & differentiate spore forming cells w/ non-spore forming cells

Give me some examples of harsh conditions required for endospores to form

Temp., pH, dehydration, UV, nutrient loss, O2 conc.

What are endospores made of?

Keratin

Name 2 genus where endospores are commonly formed

Bacillus (aerobic), clostridium (anaerobic), BOTH GRAM (+)

What crucial step is done in conjunction with malachite green?

Steaming (to get dye into endospore)

What is the purpose of the acid fast stain?

Differential stain; used to stain acid fast bacterial cell walls and differentiate acid-fast bacteria from non-acid-fast bacteria

What is special about mycobacterium (acid-fast stain)?

They have a cell wall w/ 60% mycolic acid, it is an adherence factor

What advantages does the mycobacterium cell wall have?

Protects from phagocytic digestion, dehydration, and chemicals

What crucial step is done in conjunction with addition of carbolfuchsin?

Steaming, allows dye to penetrate mycolic cell wall

What is the counterstain in the acid-fast test?

Methylene blue (to stain non-acid-fast bacteria)

Color flow chart for acid-fast

Color

What colors will the acid-fast (+) and (-) cells look like?

Acid-Fast (+) = pink

Acid-Fast (-) = blue

Give an example of a acid-fast (+) mycobacterium

Mycobacterium tuberculosis

What does the acid fast stain look like on the microscope?

What